This is what Ni looks like to me, absolutely mind blown and ponders extensively about the origins of the universe and the complexities of nature...and...and... yeah. The video explains it well.
Just kidding.
All jokes aside, the way I perceive Ni to me personally is that it is innate, especially for INJs in particular. It is a quality that one is unaware of, it just comes naturally and requires no effort-- deeply contemplating of concepts, ideas, symbolism, metaphors; and of course, having a fondness for beauty, may it be visually or metaphorically.
Ni subconsciously processes data, putting together pieces together from the outside world, which comes from our inferior function Se, and thus Ni connects through different lenses and perspectives, seeing things differently than most individuals. Like a nice, complex puzzle.
Yesterday evening, I was looking through my bedroom window and the sun was setting. Oh, it was such a beautiful sight. One of the many things I appreciate is having to see the beauty of a pink-yellow tinted sunset every evening from my window. And my mind suddenly wonders off, thinking deeply regarding the complexities of time and how quickly things go by. I later realize I have been within my own thoughts and concepts for a solid 15 minutes, just sitting in my room and pondering of all the possibilities.